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Allowance for Credit Losses (“ACL”) on Loans - Amount of Loans Receivable Held-for-Investment and Related Allowances Per Loan Portfolio Segment (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Allowance for Loan and Lease Losses [Roll Forward]
Balance at January 1, 2021	$ 39,274,000	$ 43,197,000	$ 38,973,000	$ 37,607,000
Charge-offs	(525,000)	(12,000)	(710,000)	(2,444,000)
Recoveries	133,000	9,000	216,000	52,000
Provisions (credit)	149,000	(3,701,000)	552,000	(6,075,000)
Ending balance	39,031,000	39,493,000	39,031,000	39,493,000
Originated Loans Net
Ending balance: individually evaluated for impairment	36,600		36,600		$ 30,200
Ending balance: collectively evaluated for impairment	34,836,000		34,836,000		34,211,000
Ending balance: PCD loans evaluated for impairment	4,158,000		4,158,000		4,732,000
Loans held-for-investments, net	4,111,857,000		4,111,857,000		3,806,617,000
Ending balance: individually evaluated for impairment	9,498,000		9,498,000		9,986,000
Ending balance: collectively evaluated for impairment	4,077,274,000		4,077,274,000		3,740,295,000
Ending balance: PCD loans evaluated for impairment	13,136,000		13,136,000		15,819,000
PPP loans not evaluated for impairment	11,949,000		11,949,000		40,517,000
Cumulative Effect, Period of Adoption, Adjustment
Allowance for Loan and Lease Losses [Roll Forward]
Balance at January 1, 2021				10,353,000
Cumulative Effect, Period of Adoption, Adjusted Balance
Allowance for Loan and Lease Losses [Roll Forward]
Balance at January 1, 2021				47,960,000
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Allowance for Loan and Lease Losses [Roll Forward]
Balance at January 1, 2021	34,644,000	37,915,000	34,241,000	36,726,000
Charge-offs	0	(12,000)	(185,000)	(33,000)
Recoveries	133,000	9,000	216,000	52,000
Provisions (credit)	96,000	(3,239,000)	601,000	(5,613,000)
Ending balance	34,873,000	34,673,000	34,873,000	34,673,000
Originated Loans Net
Ending balance: individually evaluated for impairment	37,000		37,000		30,000
Ending balance: collectively evaluated for impairment	34,836,000		34,836,000		34,211,000
Ending balance: PCD loans evaluated for impairment	0		0		0
Loans held-for-investments, net	4,098,721,000		4,098,721,000		3,790,798,000
Ending balance: individually evaluated for impairment	9,498,000		9,498,000		9,986,000
Ending balance: collectively evaluated for impairment	4,077,274,000		4,077,274,000		3,740,295,000
Ending balance: PCD loans evaluated for impairment	0		0		0
PPP loans not evaluated for impairment	11,949,000		11,949,000		40,517,000
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans:
Originated Loans Net
Loans held-for-investments, net	3,962,987,000		3,962,987,000		3,647,778,000
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Commercial and industrial loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance at January 1, 2021	2,954,000	2,940,000	3,173,000	1,842,000
Charge-offs	0	(12,000)	(185,000)	(12,000)
Recoveries	114,000	7,000	119,000	28,000
Provisions (credit)	(363,000)	(341,000)	(402,000)	(211,000)
Ending balance	2,705,000	2,594,000	2,705,000	2,594,000
Originated Loans Net
Ending balance: individually evaluated for impairment	18,000		18,000		1,000
Ending balance: collectively evaluated for impairment	2,687,000		2,687,000		3,172,000
Ending balance: PCD loans evaluated for impairment	0		0		0
Loans held-for-investments, net	133,422,000		133,422,000		141,005,000
Ending balance: individually evaluated for impairment	99,000		99,000		34,000
Ending balance: collectively evaluated for impairment	121,374,000		121,374,000		100,454,000
Ending balance: PCD loans evaluated for impairment	0		0		0
PPP loans not evaluated for impairment	11,949,000		11,949,000		40,517,000
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Other loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance at January 1, 2021	9,000	9,000	9,000	198,000
Charge-offs	0	0	0	0
Recoveries	0	0	0	2,000
Provisions (credit)	2,000	(2,000)	2,000	(5,000)
Ending balance	11,000	7,000	11,000	7,000
Originated Loans Net
Ending balance: individually evaluated for impairment	0		0		0
Ending balance: collectively evaluated for impairment	11,000		11,000		9,000
Ending balance: PCD loans evaluated for impairment	0		0		0
Loans held-for-investments, net	2,312,000		2,312,000		2,015,000
Ending balance: individually evaluated for impairment					0
Ending balance: collectively evaluated for impairment	2,312,000		2,312,000		2,015,000
Ending balance: PCD loans evaluated for impairment	0		0		0
PPP loans not evaluated for impairment	0		0		0
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Cumulative Effect, Period of Adoption, Adjustment
Allowance for Loan and Lease Losses [Roll Forward]
Balance at January 1, 2021				3,541,000
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Cumulative Effect, Period of Adoption, Adjustment | Commercial and industrial loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance at January 1, 2021				947,000
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Cumulative Effect, Period of Adoption, Adjustment | Other loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance at January 1, 2021				(188,000)
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Cumulative Effect, Period of Adoption, Adjusted Balance
Allowance for Loan and Lease Losses [Roll Forward]
Balance at January 1, 2021				40,267,000
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Cumulative Effect, Period of Adoption, Adjusted Balance | Commercial and industrial loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance at January 1, 2021				2,789,000
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Cumulative Effect, Period of Adoption, Adjusted Balance | Other loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance at January 1, 2021				10,000
PCD loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance at January 1, 2021	4,630,000	5,282,000	4,732,000	881,000
Charge-offs	(525,000)	0	(525,000)	(2,411,000)
Recoveries	0	0	0
Provisions (credit)	53,000	(462,000)	(49,000)	(462,000)
Ending balance	4,158,000	4,820,000	4,158,000	4,820,000
Originated Loans Net
Ending balance: individually evaluated for impairment	0		0		0
Ending balance: collectively evaluated for impairment	0		0		0
Ending balance: PCD loans evaluated for impairment	4,158,000		4,158,000		4,732,000
Loans held-for-investments, net	13,136,000		13,136,000		15,819,000
Ending balance: individually evaluated for impairment	0		0		0
Ending balance: collectively evaluated for impairment	0		0		0
Ending balance: PCD loans evaluated for impairment	13,136,000		13,136,000		15,819,000
PPP loans not evaluated for impairment	0		0		0
PCD loans | Cumulative Effect, Period of Adoption, Adjustment
Allowance for Loan and Lease Losses [Roll Forward]
Balance at January 1, 2021				6,812,000
PCD loans | Cumulative Effect, Period of Adoption, Adjusted Balance
Allowance for Loan and Lease Losses [Roll Forward]
Balance at January 1, 2021				7,693,000
Commercial | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans:
Allowance for Loan and Lease Losses [Roll Forward]
Balance at January 1, 2021	27,247,000	28,882,000	26,785,000	33,005,000
Charge-offs	0	0	0	0
Recoveries	19,000	0	97,000	19,000
Provisions (credit)	799,000	(2,342,000)	1,183,000	(4,535,000)
Ending balance	28,065,000	26,540,000	28,065,000	26,540,000
Originated Loans Net
Ending balance: individually evaluated for impairment	16,000		16,000		25,000
Ending balance: collectively evaluated for impairment	28,048,000		28,048,000		26,760,000
Ending balance: PCD loans evaluated for impairment	0		0		0
Loans held-for-investments, net	3,621,188,000		3,621,188,000		3,326,662,000
Ending balance: individually evaluated for impairment	8,679,000		8,679,000		8,352,000
Ending balance: collectively evaluated for impairment	3,612,509,000		3,612,509,000		3,318,310,000
Ending balance: PCD loans evaluated for impairment	0		0		0
PPP loans not evaluated for impairment	0		0		0
Commercial | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Cumulative Effect, Period of Adoption, Adjustment | Real estate loans:
Allowance for Loan and Lease Losses [Roll Forward]
Balance at January 1, 2021				(1,949,000)
Commercial | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Cumulative Effect, Period of Adoption, Adjusted Balance | Real estate loans:
Allowance for Loan and Lease Losses [Roll Forward]
Balance at January 1, 2021				31,056,000
One-to-four family residential mortgage | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans:
Allowance for Loan and Lease Losses [Roll Forward]
Balance at January 1, 2021	3,589,000	5,172,000	3,545,000	207,000
Charge-offs	0	0	0	(21,000)
Recoveries	0	1,000	0	2,000
Provisions (credit)	(584,000)	(563,000)	(540,000)	(811,000)
Ending balance	3,005,000	4,610,000	3,005,000	4,610,000
Originated Loans Net
Ending balance: individually evaluated for impairment	0		0		2,000
Ending balance: collectively evaluated for impairment	3,005,000		3,005,000		3,543,000
Ending balance: PCD loans evaluated for impairment	0		0		0
Loans held-for-investments, net	185,376,000		185,376,000		183,665,000
Ending balance: individually evaluated for impairment	692,000		692,000		1,562,000
Ending balance: collectively evaluated for impairment	184,684,000		184,684,000		182,103,000
Ending balance: PCD loans evaluated for impairment	0		0		0
PPP loans not evaluated for impairment	0		0		0
One-to-four family residential mortgage | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Cumulative Effect, Period of Adoption, Adjustment | Real estate loans:
Allowance for Loan and Lease Losses [Roll Forward]
Balance at January 1, 2021				5,233,000
One-to-four family residential mortgage | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Cumulative Effect, Period of Adoption, Adjusted Balance | Real estate loans:
Allowance for Loan and Lease Losses [Roll Forward]
Balance at January 1, 2021				5,440,000
Home equity and lines of credit | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans:
Allowance for Loan and Lease Losses [Roll Forward]
Balance at January 1, 2021	679,000	643,000	560,000	260,000
Charge-offs	0	0	0	0
Recoveries	0	1,000	0	1,000
Provisions (credit)	123,000	19,000	242,000	(17,000)
Ending balance	802,000	663,000	802,000	663,000
Originated Loans Net
Ending balance: individually evaluated for impairment	3,000		3,000		2,000
Ending balance: collectively evaluated for impairment	800,000		800,000		558,000
Ending balance: PCD loans evaluated for impairment	0		0		0
Loans held-for-investments, net	137,868,000		137,868,000		109,956,000
Ending balance: individually evaluated for impairment	28,000		28,000		38,000
Ending balance: collectively evaluated for impairment	137,840,000		137,840,000		109,918,000
Ending balance: PCD loans evaluated for impairment	0		0		0
PPP loans not evaluated for impairment	0		0		0
Home equity and lines of credit | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Cumulative Effect, Period of Adoption, Adjustment | Real estate loans:
Allowance for Loan and Lease Losses [Roll Forward]
Balance at January 1, 2021				419,000
Home equity and lines of credit | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Cumulative Effect, Period of Adoption, Adjusted Balance | Real estate loans:
Allowance for Loan and Lease Losses [Roll Forward]
Balance at January 1, 2021				679,000
Construction and land | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans:
Allowance for Loan and Lease Losses [Roll Forward]
Balance at January 1, 2021	166,000	269,000	169,000	1,214,000
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provisions (credit)	119,000	(10,000)	116,000	(34,000)
Ending balance	285,000	$ 259,000	285,000	259,000
Originated Loans Net
Ending balance: individually evaluated for impairment	0		0		0
Ending balance: collectively evaluated for impairment	285,000		285,000		169,000
Ending balance: PCD loans evaluated for impairment	0		0		0
Loans held-for-investments, net	18,555,000		18,555,000		27,495,000
Ending balance: individually evaluated for impairment	0		0		0
Ending balance: collectively evaluated for impairment	18,555,000		18,555,000		27,495,000
Ending balance: PCD loans evaluated for impairment	0		0		0
PPP loans not evaluated for impairment	$ 0		$ 0		$ 0
Construction and land | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Cumulative Effect, Period of Adoption, Adjustment | Real estate loans:
Allowance for Loan and Lease Losses [Roll Forward]
Balance at January 1, 2021				(921,000)
Construction and land | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Cumulative Effect, Period of Adoption, Adjusted Balance | Real estate loans:
Allowance for Loan and Lease Losses [Roll Forward]
Balance at January 1, 2021				$ 293,000

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Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 45
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Amount, excluding accrued interest, of increase in allowance for credit loss on financing receivable from recovery. Excludes net investment in lease.

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